Volkswagen TFSI / TSI (badge, not an engine)

TFSI and TSI are badges, not engines — turbocharged fuel stratified injection, which describes a fuel system rather than a design.

Our rows show them on 1.0 to 4.0 litres across Volkswagen, Audi and SEAT, covering at least the EA211 and EA888 families, plus the V6s and V8s. A 1.0 three-cylinder Polo and a 4.0 V8 share a badge and nothing else.

Establish the EA number, which is what every technical source uses and what this catalogue files these engines under.

What the badge does tell you is the fuel system, and that is genuinely consequential. Direct injection with no port injector behind it means there is no petrol washing the back of the inlet valve — so oil mist from the crankcase breather bakes onto it and stays.

Carbon build-up on the inlet valves is therefore a maintenance item rather than a fault on almost everything wearing this badge: rough running at idle and light load, a misfire that comes and goes, at 100,000 km on an engine that is otherwise sound. It is cleaned, not repaired.

Later engines added a port injector alongside precisely to solve this, so the model year decides whether the problem applies at all — which is a distinction the badge does not make and a great deal of forum advice ignores.

The EA888's timing chain tensioner on the early versions, and the EA211's wet-belt-free chain, are family matters and belong on those pages.